Differences in Somatosensory Function Related to Hand Dominance: Results of a Quantitative Sensory Testing Study in Healthy Volunteers.

Purpose: Quantitative sensory testing commonly utilizes the unaffected, contralateral side as a control to detect somatosensory dysfunction. There is scant evidence that somatosensory function for the volar dominant and non-dominant hands is equivalent, therefore intra-patient comparisons are unwarranted. This study aimed to identify dominance-related differences in palmar hand somatosensation, thereby determining if the unaffected contralateral hand is a valid comparator in clinical populations. Participants and Methods: With ethical approval (IREC_13_1_10) and informed consent, 110 healthy adult volunteers' participated in this clinical measurement study. Somatosensory function was assessed with the German Research Network on Neuropathic Pain (DFNS) quantitative sensory testing (QST) protocol. Half of the participants were tested on the dominant hand. Thirteen parameters of thermal and mechanical detection and pain threshold were evaluated at both the dorsal and volar hand (distal middle finger). Tests were performed in the same order and instructions were read from a standardized script. Results for dorsal hand tests were compared to DFNS normative data to confirm participants met study inclusion criteria. Between-group differences for age and sex were investigated with the independent samples t-test and Chi-square test of independence, respectively. Group differences for dominant and non-dominant hands for all 13 continuous QST parameters were investigated with the Mann-Whitney U-test. Results: Data for 106 participants were included in statistical analysis. Fifty percent of participants were tested on the dominant hand [n=53]; there were no differences for age or sex between groups (dominant or non-dominant hand test group). The dominant volar hand was significantly more sensitive to vibration detection threshold than the non-dominant hand (P=0.001). There were no significant differences related to dominance for other DFNS QST measures. Conclusion: For quantitative sensory testing with the DFNS protocol in healthy cohorts, the contralateral, unaffected hand is a valid control, with the exception of vibration detection threshold.

Morphology and distribution of antennal sensilla in five species of solitary bees (Hymenoptera, Apoidea).

Solitary bees play a crucial role in ecological systems, contributing to the pollination of crops and wild plants. All females are reproductive, and their habitat requirements include nesting sites, food resources and nesting materials. Although these activities require the ability to detect biotic and abiotic stimuli in the environment, the sensory system of these species is poorly studied. In this study, the antennal sensilla of five solitary bee species belonging to three Apoidea families were investigated using scanning electron microscopy. These included two species of stem-nesting bees, Ceratina cucurbitina (Rossi, 1792) (Apidae) and Osmia scutellaris (Morawitz, 1868) (Megachilidae), and three species of ground-nesting bees, Lasioglossum brevicorne (Schenck, 1870), Lasioglossum leucozonium (Schrank, 1781), and Lasioglossum villosulum (Kirby, 1802) (Halictidae). Thirteen different types of antennal sensilla were identified in females based on their morphological characteristics: sensilla trichodea (subtypes STI, II, III), chaetica (subtypes SchI, II), basiconica (subtypes SBI, II, III, IV), placodea, campaniformia, coeloconica, and ampullacea. Their functional role was discussed and morphology was compared among the species and within the antennal segments in each species. The results provide a baseline for further physiological and behavioural studies to determine the role of antennal sensilla in habitat selection, food search and nesting site selection.

Administration of Essential Phospholipids Prevents Drosophila Melanogaster Oocytes from Responding to Change in Gravity.

The aim of this study was to prevent initial changes in Drosophila melanogaster oocytes under simulated weightlessness and hypergravity at the 2 g level. Phospholipids with polyunsaturated fatty acids in the tail groups (essential phospholipids) at a concentration of 500 mg/kg of nutrient medium were used as a protective agent. Cell stiffness was determined using atomic force microscopy, the change in the oocytes' area was assessed as a mark of deformation, and the contents of cholesterol and neutral lipids were determined using fluorescence microscopy. The results indicate that the administration of essential phospholipids leads to a decrease in the cholesterol content in the oocytes' membranes by 13% (p < 0.05). The stiffness of oocytes from flies that received essential phospholipids was 14% higher (p < 0.05) and did not change during 6 h of simulated weightlessness or hypergravity, and neither did the area, which indicates their resistance to deformation. Moreover, the exposure to simulated weightlessness and hypergravity of oocytes from flies that received a standard nutrient medium led to a more intense loss of cholesterol from cell membranes after 30 min by 13% and 18% (p < 0.05), respectively, compared to the control, but essential phospholipids prevented this effect.

Notes of the trichobothrial patterns in damsel bugs (Insecta: Hemiptera: Nabidae).

A trichobothrium is a complex sensory organ, which usually consists of a long, slender mechanoreceptive seta (trich), which is situated in a cuplike depression in the cuticle (bothrium). Nabidae (Hemiptera: Heteroptera: Cimicomorpha), also called damsel bugs, are a relatively small family within which two subfamilies, Nabinae and Prostemmatinae, are distinguished. Trichobothria are present in the number of one to seven pairs located laterally on the scutellum of adult representatives of Prostemmatinae. This feature is commonly used to distinguish this subfamily from Nabinae. Trichobothria are also found on the abdominal tergites of Prostemmatinae nymphs. Similar sensilla have been observed in adult representatives of Nabinae, but their homology has not yet been confirmed. During morphological studies on Nabidae, conducted using scanning electron microscopy, we noticed sensilla resembling trichobothria on the heads of these insects. This discovery prompted us to examine the presence of these structures in damsel bugs more carefully. Imagines of fifteen species of both subfamilies were analysed using a scanning electron microscope. The results present data on the distribution and micromorphology of the trichobothria in damsel bugs. A pair of dorsal and ventral cephalic trichobothria were observed in all of the examined species of subfamily Nabinae. These sensilla were not found on the heads of Prostemmatinae. The results of studies on scutellar trichobothria confirmed the previously known data regarding their occurrence in Prostemmatinae. Moreover, our research showed the presence of these sensory structures in all of the examined Nabinae species: one pair of trichobothria in Arachnocorini, Carthasini, Gorpini and Nabini, and two pairs in Stenonabini. The presence of abdominal trichobothria was shown in Nabini and Stenonabini. In the remaining studied tribes of Nabinae and in the subfamily Prostemmatinae, the presence of structures that could undoubtedly be considered abdominal trichobothria was not found.

Evidence for tactile 3D shape discrimination by octopus.

Octopuses integrate visual, chemical and tactile sensory information while foraging and feeding in complex marine habitats. The respective roles of these modes are of interest ecologically, neurobiologically, and for development of engineered soft robotic arms. While vision guides their foraging path, benthic octopuses primarily search "blindly" with their arms to find visually hidden prey amidst rocks, crevices and coral heads. Each octopus arm is lined with hundreds of suckers that possess a combination of chemo- and mechanoreceptors to distinguish prey. Contact chemoreception has been demonstrated in lab tests, but mechanotactile sensing is less well characterized. We designed a non-invasive live animal behavioral assay that isolated mechanosensory capabilities of Octopus bimaculoides arms and suckers to discriminate among five resin 3D-printed prey and non-prey shapes (all with identical chemical signatures). Each shape was introduced inside a rock dome and was only accessible to the octopus' arms. Octopuses' responses were variable. Young octopuses discriminated the crab prey shape from the control, whereas older octopuses did not. These experiments suggest that mechanotactile sensing of 3D shapes may aid in prey discrimination; however, (i) chemo-tactile information may be prioritized over mechanotactile information in prey discrimination, and (ii) mechanosensory capability may decline with age.

Biomechanics of transduction by mechanosensory cilia for prey detection in aquatic organisms.

Surface-feeding aquatic animals navigate towards the source of water disturbances and must differentiate prey from other environmental stimuli. Medicinal leeches locate prey, in part, using a distribution of mechanosensory hairs along their body that deflect under fluid flow. Leech's behavioral responses to surface wave temporal frequency are well documented. However, a surface wave's temporal frequency depends on many underlying environmental and fluid properties that vary substantially in natural habitats (e.g., water depth, temperature). The impact of these variables on neural response and behavior is unknown. Here, we developed a physics-based leech mechanosensor model to examine the impact of environmental and fluid properties on neural response. Our model used the physical properties of a leech cilium and was verified against existing behavioral and electrophysiological data. The model's peak response occurred with waves where the effects of gravity and surface tension were nearly equal (i.e., the phase velocity minimum). This suggests that preferred stimuli are related to the interaction between fundamental properties of the surrounding medium and the mechanical properties of the sensor. This interaction likely tunes the sensor to detect the nondispersive components of the signal, filtering out irrelevant ambient stimuli, and may be a general property of cilia across the animal kingdom.

Using electric fields to control insects: current applications and future directions.

Chemical-based interventions are mostly used to control insects that are harmful to human health and agriculture or that simply cause a nuisance. An overreliance on these insecticides however raises concerns for the environment, human health, and the development of resistance, not only in the target species. As such, there is a critical need for the development of novel nonchemical technologies to control insects. Electrocution traps using UV light as an attractant are one classical nonchemical approach to insect control but lack the specificity necessary to target only pest insects and to avoid harmless or beneficial species. Here we review the fundamental physics behind electric fields (EFs) and place them in context with electromagnetic fields more broadly. We then focus on how novel uses of strong EFs, some of which are being piloted in the field and laboratory, have the potential to repel, capture, or kill (electrocute) insects without the negative side effects of other classical approaches. As EF-insect science remains in its infancy, we provide recommendations for future areas of research in EF-insect science.

Hemodynamic force dictates endothelial angiogenesis through MIEN1-ERK/MAPK-signaling axis.

It is well-recognized that blood flow at branches and bends of arteries generates disturbed shear stress, which plays a crucial in driving atherosclerosis. Flow-generated fluid shear stress (FSS), as one of the key hemodynamic factors, is appreciated for its critical involvement in regulating angiogenesis to facilitate wound healing and tissue repair. Endothelial cells can directly sense FSS but the mechanobiological mechanism by which they decode different patterns of FSS to trigger angiogenesis remains unclear. In the current study, laminar shear stress (LSS, 15 dyn/cm2) was employed to mimic physiological blood flow, while disturbed shear stress (DSS, ranging from 0.5 ± 4 dyn/cm2) was applied to simulate pathological conditions. The aim was to investigate how these distinct types of blood flow regulated endothelial angiogenesis. Initially, we observed that DSS impaired angiogenesis and downregulated endogenous vascular endothelial growth factor B (VEGFB) expression compared to LSS. We further found that the changes in membrane protein, migration and invasion enhancer 1 (MIEN1) play a role in regulating ERK/MAPK signaling, thereby contributing to endothelial angiogenesis in response to FSS. We also showed the involvement of MIEN1-directed cytoskeleton organization. These findings suggest the significance of shear stress in endothelial angiogenesis, thereby enhancing our understanding of the alterations in angiogenesis that occur during the transition from physiological to pathological blood flow.

Sensory-mediated feeding behaviour in the larvae of marble goby (Oxyeleotris marmorata).

This study was conducted to determine the senses that facilitate prey detection in the marble goby (Oxyeleotris marmorata) larvae. The ingestion ratios of live (generate chemical and mechanical stimuli) or frozen Artemia nauplii (generate chemical but no mechanical stimuli) by the intact or free neuromast (mechanoreceptor)-ablated O. marmorata larvae (11 mg/L streptomycin treatment before feeding) under the light or dark (fish vision was obstructed) condition were examined. Vision, mechano-, and chemoreceptions were all found to be essential in prey detection of the O. marmorata larvae. Prey movement has a significant influence as a visual stimuli on the O. marmorata larval feeding as the Artemia nauplii ingestion ratio was approximately 40% higher with significant (p = 0.001, d = 3.0), when the intact larvae were fed with the live (78.1 ± 1.5%), rather than the frozen (40.9 ± 2.8%) Artemia nauplii, under the light condition. This result was assured when no significant difference (p = 0.572, d = 0.2) was found between the ingestion ratios of frozen Artemia nauplii by the intact O. marmorata larvae under light and dark conditions. These findings demonstrate that prey detection in the O. marmorata larvae was facilitated by multi-modal senses, allowing O. marmorata larvae to survive in their natural habitats.

Describing whisker morphology of the Carnivora.

One of the largest ecological transitions in carnivoran evolution was the shift from terrestrial to aquatic lifestyles, which has driven morphological diversity in skulls and other skeletal structures. In this paper, we investigate the association between those lifestyles and whisker morphology. However, comparing whisker morphology over a range of species is challenging since the number of whiskers and their positions on the mystacial pads vary between species. Also, each whisker will be at a different stage of growth and may have incurred damage due to wear and tear. Identifying a way to easily capture whisker morphology in a small number of whisker samples would be beneficial. Here, we describe individual and species variation in whisker morphology from two-dimensional scans in red fox, European otter and grey seal. A comparison of long, caudal whiskers shows inter-species differences most clearly. We go on to describe global whisker shape in 24 species of carnivorans, using linear approximations of curvature and taper, as well as traditional morphometric methods. We also qualitatively examine surface texture, or the presence of scales, using scanning electron micrographs. We show that gross whisker shape is highly conserved, with whisker curvature and taper obeying simple linear relationships with length. However, measures of whisker base radius, length, and maybe even curvature, can vary between species and substrate preferences. Specifically, the aquatic species in our sample have thicker, shorter whiskers that are smoother, with less scales present than those of terrestrial species. We suggest that these thicker whiskers may be stiffer and able to maintain their shape and position during underwater sensing, but being stiffer may also increase wear.